1. Field of the Invention
This invention relates to the field of navigation. More specifically, the invention comprises a user interface providing information about obstacles in the users environment.
2. Description of the Related Art
The present invention is suitable for use in the operation of a wide range of applications where a user is maneuvering around obstacles. It is particularly advantageous in cases where peripheral vision is limited. For example, the system may be used to assist the driver of an armored vehicle such as a tank. As a second example, the invention is useful in the operation of passenger vehicles, where the invention assists the driver in staying in the proper lane and maintaining traffic separation. Another useful application is the operation of remotely operated vehicles, where the operator's view may be limited by the orientation of a particular sensor or the vehicle itself. All the examples described in detail involve remotely operated vehicles. However, the reader should bear in mind that the invention may be applied to other fields of endeavor. As an example, the invention may be used to assist a firefighter maneuvering on foot.
FIGS. 1-5 illustrate a situation that is commonly encountered when a user operates a remotely controlled vehicle. FIG. 1 depicts a very simplistic remotely operated vehicle—robot 10. Chassis 16 is propelled by a right track 12 and left track 14. The speed and direction of each track may be individually controlled, thereby providing a wide range of desirable motions. Video camera 18 captures and transmits a live feed of the terrain in front of robot 10. The video feed is provided to a remote operator. The operator is able to transmit commands to control the motion of the robot to achieve a desired result.
The use of a video feed provides a great deal of information to a skilled operator. However, it is also limited in several significant ways. FIG. 2 presents a situation where robot 10 is being maneuvered to avoid obstacles in its path. Walls 22 and 24 meet at corner 26. Opening 28 is located in wall 22. The remote operator can see opening 28 via the live video feed. However, the video feed provides limited depth perception.
FIG. 3 depicts the view a remotely-located operator might see on a video display. Video display 20 depicts all the critical features in the robot's surrounding (wall 22, wall 24, corner 26, and opening 28). However, limited range and dimensional information is provided. The information that is available must be judged by relative sizes, which relies heavily on operator experience. As a result, it is often difficult for even experienced operators to tell how large opening 28 is. For instance, the operator may perceive that opening 28 is a small opening in a wall that is very close to robot 10. The operator may also perceive that opening 28 is a large opening in a wall that is quite far away.
For a human being standing in the position of robot 10, this ambiguity would be resolved via binocular vision and other cues (such as parallax created by head movement). It is possible to provide two cameras on the robot in order to create a parallax effect that can be used to drive 3D-simulating viewing devices. However, these systems are complex and somewhat cumbersome to use. Most remotely operated vehicles only provide a single video feed. Additionally, the precision provided by binocular vision systems, whether human or camera-based, is often insufficient to judge low-margin openings.
Another significant limitation of relying on a video feed is the camera's field of view. FIG. 4 shows a plan view of robot 10 confronting the same obstacles depicted in FIGS. 2 and 3. The operator cannot see beyond the arc denoted as camera field of view 30. Central axis 32 is a line drawn through the robot's center and extended forward. In the embodiment shown, video camera 18 is centered on central axis 32. Thus, camera field of view 30 extends equally to either side of central axis 32.
The field of view depicted is actually fairly wide. However, it cannot show objects that are immediately adjacent to the robot's right and left forward extremities. The location of such objects is particularly important when attempting to maneuver a robot through opening 28. The operator cannot easily tell when the robot has passed through the opening, nor can the operator tell whether adequate clearance has been maintained on either side.
Prior art devices have recognized the shortcomings inherent in the use of video alone. Prior devices have augmented the video feed with other sensory data. FIG. 5 shows one such device. In FIG. 5, ranging device 36 has been placed on the front of the robot. A “ranging device” is any device that can accurately determine a range from a vehicle to an object. Most such devices determine a range along a vector originating at the ranging device itself. The emitter shown in FIG. 5 is able to scan a 180 degree arc, extending from the left side of the robot to the right side of the robot (ranging field of view 34). Other ranging devices may scan a 270 degree arc or a 360 degree arc. The data retrieved is typically fed to a computing device that then determines the position of numerous data points 38. These data points may then be depicted on a display such as shown in FIG. 5.
The plotting of data points 38 may be better than the video feed alone, but it does not provide readily-integrated information to the operator. The operator's attention will generally be focused on the video feed, as it will be the basic tool for target identification, situational awareness, obstacle identification, etc. An effective user interface would preferably exploit the natural operation of human visual processing. It is now recognized that human visual processing occurs in two parallel channels. These are generally referred to as the focal channel and the ambient channel. The focal channel is used when a person focuses on a single specific object. The ambient channel monitors the surrounding scene in a much broader way. Both channels process information simultaneously. The video display customarily occupies the focal channel. It would be advantageous to provide a user interface that utilizes the ambient channel as well. The present invention uses both channels.